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RE: Piston Slap ? Non LSR

To: land-speed@autox.team.net
Subject: RE: Piston Slap ? Non LSR
From: "Dave Dahlgren" <ddahlgren@snet.net>
Date: Sat, 27 Dec 2003 07:26:58 -0500
With 62k on the engine I would do 2 things. Change to 20-50 oil. The brand
new clearances are probably gone by now. See if they have a way to
decorbonize the engine. If it has a throttle body injection it is easy. just
very slowly pour some water from a small cup down the throttle body with the
engine running at around 2k warmed up. Pour it just fast enough to lose
around 100 or 200 rpm and you have to give it a little throttle by hand to
maintain 2k rpm. If there is a lot of carbon built up between the pistons
and head from all the long warm up time that should take care of it though
you may have to do it twice. Ford had it's fair share of problems with this
on some models but I suspect it was owner related as well. If you don't have
a throttle body and the dealer has a way to do this without disassembly give
that a try as well. There may be chemicals that are better now and you might
ask the local parts store.

What the dealer is telling you is all these engines have the same failure
mode and inferring that since they all do it ,it must be ok.. Ask the dealer
what makes the noise that is ok and why the engine did not do it when new.
Ask as well if the parts are hitting each other hard enough to make the
noise how is that ok? If it is 'piston slap' it means one of several things.

The pistons skirts are collapsed.. not good..
Pistons are cracked.. not good
Piston to wall clearances have opened up too much.. not good

If it is under warrantee I would make them fix it. Especially if it can be
documented as a chronic problem with that engine model as that makes it a
design issue as well even if it is off warrantee.
I did a google search on the net and found these pretty quick.
Some of them mention carbon build up but if it was that easy I suspect GM
would have done the quick and dirty fix I recommended right away rather than
buy trucks back. Have some fun ask the dealer what he will give you for it
with the noise..

http://www.consumeraffairs.com/news03/gm_buyback.html
http://asia.news.yahoo.com/031114/3/17tya.html
http://www.motortrend.com/features/news/112_news51/
http://motorway.pasadenastarnews.com/Stories/0,1413,249%257E25859%257E178945
7,00.html
http://www.pistonslap.com

as usual your mileage may vary and the fixes I suggested are experiments to
certain degree so try them at your own risk as well
Dave Dahlgren






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